"I'm in the business now where I think very little shocks you about professional football, particularly in the last 10 years.

"Coming into the football club at the time when the club was on its knees, and I believe I saved the club from relegation last year, I felt the opportunity [to stay at the club] should have still been afforded to me."

Sakced: O'Neill sparked an upturn in form when he took over but couldn't sustain it this term

O'Neill took over from Steve Bruce in December 2011 with the team in the bottom three but he revived the club and got them to 13th.

But a run of eight games without a win, plunging his side to within a point of the relegation zone, ended his spell.

O'Neill is keen to get back into football management and still loves the game, despite his departure from Sunderland.

He has been hit hard by the sudden sacking which came as a surprise as owner Ellis Short moved to shake up the club and avert relegation and financial disaster.

Asked about the criticism of his tactics in the last week by pundits, O'Neill admitted to being annoyed.

He added: "I've heard this word mentioned. You talk about a dinosaur. The biggest dinosaur in the game happens to be the best manager in the game and he has been for years. He'll go down in history as one of the greats.

"I'm talking about Sir Alex Ferguson. There's no bigger dinosaur.

"He's 70 years of age, too - he's gone with the times. I don't accept this.

"Also, it's interesting that England turn to Roy Hodgson to be their manager with all that experience of international football and club football all over Europe [Hodgson will be 66 in August]. They turn to him, because he's got this experience, but not only that he's been involved in the game for a long time and he's got the know-how.

"So they've turned to him. Queens Park Rangers turned to Harry Redknapp [Redknapp is 66]. So everybody has a shelf-life but it doesn't depend on age."

O'Neill was prickly when pushed to say what he thought of successor Di Canio.

He added: "I've got nothing to say about that. That's part of Sunderland's future now and it's their prerogative to do what they want.

"I think he has mentioned he expects to keep Sunderland up and that's fine. He thinks he'll be able to do it and that's why he has been brought in. He has said he'll do it, that's up to him.

"You keep coming back to me again [on whether I think he is a good appointment], I've just said there is no answer coming back from me.

"The DNA of Sunderland football club is about passion. It really is about passion and has been throughout the years and that is very important - it's very important to supporters of the football club, very important indeed.

"But it carries you a certain distance, you've got to have the ability to play.

"Overall, some very fine players play at Sunderland at this moment but we haven't got enough true ability throughout the side to be able to cope with every single thing that's thrown at us.

"I don't think it's a major criticism. It's there for all to see. It's actually a fact.

"But it's something you have to try and cure and want to rectify as soon as possible. That's not always possible, given the time."

Paolo Di Canio's five-point plan

The five things the new Sunderland manager must do to keep them in the Premier League, by Simon Bird

GOALS Di Canio spent his first few training sessions concentrating on his strikers, and how to carve out more chances. Not surprising, since Sunderland have only scored 33 league goals this season. With leading scorer Steven Fletcher out injured, the onus is on Danny Graham and Connor Wickham to chip in. Both have had one-to-one pep talks this week, and intensive training.

CONFIDENCE O’Neill pin-pointed ­confidence as a problem. He wanted to get his players to try the creative, or patient pass – not one an impatient crowd might demand. Heads have dropped in the squad on a run of eight games without a win. Di Canio says one of his guiding principles is collective spirit and a ban on a blame culture among players.

ADAM JOHNSON The England international was supposed to be a game-changer for Sunderland, but his form has been mediocre. On his day, the North-East native is capable of opening doors. Di Canio needs to give him the key. Johnson has the highest profile, and can’t be expected to transform the team, with similar applied to all the club’s creative players, including Stephane Sessegnon and James McClean.

LEADERSHIP Di Canio’s personality may not be to everyone’s taste but Sunderland need some of his spiky attitude on the pitch. With captain Lee Cattermole injured, they have little bite and it is a quiet dressing room. John O’Shea, Cattermole’s deputy, is not a shouter. He and other senior players must step up – it’s no time for shrinking violets.

The F-WORD Football, not fascism. Sunderland have hit the headlines for all the wrong reasons, and amid that the idea behind Di Canio’s appointment has been lost. Namely, they are sleepwalking to relegation. With seven games to play, including Sunday at Stamford Bridge and next week’s derby against Newcastle, clear heads are required.